Weightlifting is a common type of activity for the development of strength and size of skeletal muscles. Weightlifting generally utilizes the weight force of gravity (in the form of weighted bars, and/or weighted disc plates) to oppose the force generated by muscle through concentric or eccentric contractions. Thus, the use of free weights such as a barbell with disc-weights helps increase the strength and tone of muscles in the arms, upper body, and lower body of the user through various exercises.
Although barbells allow a weightlifter to accommodate a significant amount of weight due to the two handed control and balance, barbells may not be best suited for certain exercises. Specifically, when using a barbell, a user may be unable to properly isolate specific muscle groups during weight lifting exercises. Users may also be unable to perform exercises that are directed to adjusting the resistance relative to the center gravity of a barbell.
In particular, barbells generally have only have two basic positions in which a user's arms may be positioned (i.e., palms up and palms down). While these positions may be adjusted to some degree (by repositioning the user's palms along the horizontal bar) to isolate certain muscle groups or vary particular exercises, every other possible position and variation of the user's arms is usually restrained by the fact that the bar is generally straight and unitary.
To overcome this problem of limited variations and use, different types of special barbells have been created. For example, a curling barbell having V-shaped grip portions along its length has been created, so that the user may hold the bar with his or her wrists positioned inwards or outwards at an angle to isolate specific muscle groups in the arm or minimize discomfort when performing a curl exercise. An extension bar which generally has two handles disposed perpendicular to the length of the barbell has also been created, so that the user's palms can face inwards or towards each other, thereby better isolating the triceps.
Despite the advantages of the above-mentioned reconfigured barbells, these barbells do not completely address the issue of varying the resistance in relation to the center of gravity or horizontal plane of the barbell. Rather, the above-mentioned barbells are only directed to isolating particular muscle groups by repositioning the user's hands and arms with respect to the barbell.
Thus, what is needed is device that varies the sense of resistance of a barbell with respect to the center of gravity and/or horizontal plane of the barbell. Preferably, the device may be attached to a standard barbell or barbell-like devices and may be used to provide the user with resistance relative the horizontal plane of the barbell as well as the manner in which the task is performed. Furthermore, versatility in the manner of attachment may also be beneficial.